Fig 1: Role for topoisomerase 2a (TOP2A) in the cell toxicity of CX-5461.(A) Viability assay on wild-type (WT) and seven CX-5461-resistant (CXR) HAP1 clones treated with CX-5461. Error bars represent SD from the means, n = 3 independent experiments. (B) Representation of genes with non- and mis-sense mutations identified in CXR clones. Mutated genes identified in resistant clones (blue rectangles) are represented as yellow ovals. The presence of a TOP2A mutation in all resistant clones is schematized by the central position of TOP2A gene in the red oval. Solid and dashed lines represent respectively mutations characterized through an unbiased or manual analysis of RNA-seq data. (C) Linear schematic of TOP2A domains. Each domain is labeled and described by bordering residue numbers. TOP2A mutations present in CX-5461 or F14512-resistant clones are indicated in blue or red, respectively. (D) Immunoblotting analysis of whole-cell extracts from WT (Ctrl) and CXR HAP1 cells. Relative protein levels of TOP2A and TOP2B were quantified, normalized to KU80 level, and set to 100 in Ctrl cells.Figure 1—source data 1.Raw unedited image and uncropped figure of the blot of the western blot from Figure 1.Ponceau staining (left panels), membranes (center panels), and hybridization signals (right panels) are shown. Raw images were acquired using the ChemiDoc system (Bio-Rad). Asterisks indicate the edges of cut membranes before hybridization.